1. Field of the Invention
This invention relates generally to devices in which spinning disks are maintained in a contaminant free environment, such as Winchester Drive mechanisms, and more particularly to an improved structure and method for dynamically maintaining the integrity of the enclosure with regard to leakage of contaminated air into the enclosure.
2. Description of the Prior Art
As is well known, the so-called Winchester Drive disk storage system for computer data is one of the more effective and efficient means of providing dense storage and rapid access. Such advanced forms of memory storage utilize a flying head, which is maintained at a distance on the order of 0.5 to 1 microns above a magnetic oxide coating carried on an aluminum substrate, with the oxide coating rotated past the flying head to maintain the clearance as a function of an air layer carried by the disk. Such submicron dimensions while providing for dense recording of data upon the disk concurrently required clean room conditions. For instance, a small smoke particle or fingerprint smudge may often be an order of magnitude greater than the clearance between the flying head and oxide coating, thus precipitating a crash of the head relative to the rotating disk if carried into the smaller gap between the head and disk. Simple dust particles consitute massive interference for purposes of Winchester Drive mechanisms.
Winchester Drive mechanisms are, of course, manufactured under clean room conditions. The disk and head mechanisms are enclosed for protection from normal contaminated working environments. In the larger and more expensive disk devices, involved filtering and other such support systems for the operating environment are provided. However, in the smaller variations of the Winchester Drive mechanism available, i.e., those with the smaller disks which are intended for use with smaller, less expensive installations, simpler provisions must be made to protect the clean environment.
Typically, the more basic devices utilize an air circulation system in which the spinning disk flows air around the periphery of the enclosure. The enclosure is sealed, and an internal filter is positioned in the circulation flow induced by the spinning disk to entrap contaminants. Ventilation to the ambient atmosphere has, at least in a more popular embodiment, been wherever a bulky filter could be positioned, i.e., not at the spindle because of space limitations, such that contaminants passing through various unavoidable leaks into the enclosure would be caught up in the internal circulation until trapped by the internal filter. Contaminants entering at leaks into the enclosure would thus circulate within the enclosure with the possibility of coming to rest upon the spinning disk, with the above described serious results.